Bi Directional Communication - What Is It!

How old is your printer?  If the printer doesn't support it then you don't need a new cable.  All relatively new printers will do a printer communication test and let you know if bidirectional printing is enabled and functioning.  If you have a cable marked appropriately (I believe it is IEEE 1584) then you have a bidirectional cable.  Of course, a printer communication test would let you know if it is working in bidirectional mode.  Give us more info on printer type along with any markings on your cable and maybe we can help more.

Bidirectional communication lets the printer give information back to the computer.  Examples of this could be, paper jams, printing job done, low on toner.

All modern printers use Bi-directional communication (Printer<-->PC)to communicate with the PC (printer driver). Events like paper end, low ink and other status messages are displayed on the PC and will ask for user actions.You must set onboard parallel port mode to Bi-dir from the BIOS.  

Epson Stylus Colour 880 (Brand New) There are no markngs on the cable, however, the status for ink does appear and the communication between printer and computer is excellent. It knows exactly what is wrong with it. One thing bothers me however. Epson help manual states that :-
Bi-di =

This setting activates bidirectional printing so your printer prints both left-to-right and right-to-left. High Speed mode speeds up printing, but decreases print quality.
Note: If misaligned vertical lines appear when printing in High Speed mode, you may need to align the print heads.

All rights reserved.

However, i have watched it print and it only prints on the out stroke, not the return stroke. So, is it not owkring. I'm not sure about bi di in the bios, i was advised by epson to change the parallel port to ecp. Which i did, to "enable high speed dma transfer" I didn't come accross any settings for bi di

Hope this helps

Well I guess we read that one wrong.  Obviously bi-directional is faster that unidirectional.  How is the driver set up?  Is it set up for bidirectional printing?  Is the quality set to High?  If so, I believe the statement above indicates that you can't have bidirectional printing coupled with good quiality.
You appear to have the right cable and connection.  The next thing is to tweak your driver so that you can get the functionality you want.  I have dealt with Epson Stylus printers and they are quite slow.  It comes down to a choice between quality and speed.

Speeeeeeed!!!!!

Gimmie more speed! Windows Driver says that bi di is enabled. (Printer Properties>Spool Settings> Enable BI Di for this device is selected. (What is faster RAW or EMF, just out of interest?)

I don't believe RAW or EMF will make a speed diff.  What quality printout is selected.  The lower quality you select the more speed you will get.

Note that the documentation you've quoted says "High Speed mode speeds up printing, but decreases print quality."

You may need to select 'Draft' mode or similar to get the two way printing to work.

Furthermore, if you resort to calling Epson about this, they'll be just as confused as the experts here if you referenced the cable and parallel port.  This is NOT a port or cable issue, but a printer setup issue.  References to the port or the cable confuses matters.  As long as the computer has the ink status information, the printer is successfully communicating back to the computer thus the port and cable are doing the bidirectional thing.

regards,
magarity

"All modern printers use Bi-directional communication (Printer<-->PC)to communicate with the PC (printer
driver). Events like paper end, low ink and other status messages are displayed on the PC and will ask
for user actions.You must set onboard parallel port mode to Bi-dir from the BIOS."

Really! All modern printers use Bi-directional communication.  I could have sworn they were making USB drives these days. Mine is. %-)

It should actually be set each time you print If your Epson is like my 580 it goes back to defaults after each print job is completed.  I have to set mine for high speed each time I want high speed.  Otherwise, it makes the compromise (speed vs quality) for me.

What i meant was bi directional printing. From what the status monitor tells me, bi directional communication is enabled. Would it make any difference if i used the usb interface instead? I was told that usb supports bi di.

I know less quality = less speed. But bi di printing also equals less quality (according to epson)

Is USB a better idea? Is it faster than parallel.

I think that you cheat us: your question is:
>>>Question: Bi Directional Communication - What Is It!
After that you ask for bi-directional PRINTING
and after that you ask for USB interface vs. parrallel.
USB is fastest that parallel.

Read "faster than" Sorry.

This is true.  Your initial and subsequent question were answered.  You should accept and post another question.
The print speed has nothing to do with how fast you can receive data.  If you want printing speed for text get a fast dot matrix printer such as the Okidata Pacemark 3410.  If you want fast laser printing you can get lasers that print 19 ppm or better.  I think you are mistakenly tying together communication and output speed.  They are completely separate.

Thanks, I'll go for the usb option. I know for a fact now that it is faster and that it supports bi di fully.

It won't help you print faster, though!!

Yeah, i have to decrease print quality for that to happen. I mean the data will get through quicker